1. Field of Invention
This invention generally relates to the field of information ranking and retrieval.
2. Description of Related Art
A notoriously difficult problem in using large heterogeneous document collections, such as the World Wide Web (the “Web”), is that it is not easy to recognize which documents, for example, which web pages and web documents, provide reliable authoritative information about a subject. The problem is particularly significant where it concerns “high-value” informational needs, such as retrieving medical information, where the cost of error may be high.
Authoritativeness of a web page or document is commonly measured based on social networks represented by the link structure of the Web. “The anatomy of a large-scale hypertextual (web) search engine,” by S. Brin et al., 7th International World Wide Web Conference, 1998, and “Authoritative sources in a hyperlinked environment,” by J. Kleinberg, Proc. of the 9th ACM-SIAM Symposium on Discrete Algorithms, 1998, each of which is incorporated herein by reference in its entirety, respectively discuss the algorithm used by the PageRank® search engine implemented by the search site Google® and HITS® algorithm.